1. Technical Field
The present invention relates to liquid consumption apparatuses.
2. Related Art
Printing apparatuses using an inkjet system, which are an example of a liquid consumption apparatus, are fitted with ink cartridges, which are removable liquid containers. There are ink cartridges that are provided with a prism for detecting that the amount of ink in the ink cartridge has fallen below a predetermined amount. Detection of the residual state of ink using a prism can be performed based, for instance, on the intensity level of light that is incident on a light receiving element, utilizing the fact that when light irradiated by a light emitting element is incident on the prism and reflected by the sloped surfaces at the apex of the prism, the reflective state differs depending on whether the sloped surfaces are in contact with ink.
In JP-A-10-232157, in order to prevent light that has passed through the prism and into the ink inside the ink cartridge from again being incident on the prism and received by the light receiving element after being reflected by the interface between the upper ink surface and air in the ink cartridge, technology is disclosed for installing a structure for suppressing reflection by the interface between the upper ink surface and air inside the ink cartridge. However, there are cases where reflection is produced not only by the interface between the upper ink surface and air in the ink cartridge but also by the surface of the prism on which the light is incident. Such reflection cannot be suppressed with the technology disclosed in JP-A-10-232157.
JP-A-10-232157 and JP-A-2002-264355 are examples of related art.